$(document).ready(function(){
    $('.nav_content_item').click(function() {
        $('.nav_content_item').find('span').removeClass('nav_span_select').removeClass('nav_span_unselect');
        $(this).find('span').addClass('nav_span_select');
        $('.nav_content_item').not(this).find('span').addClass('nav_span_unselect');
        let index = $(this).data("index");
        switch (index){
            case 0:
                var url = "index.html";
                window.open(url, '_blank');
                break;
            case 1:
                var url = "html/survey.html";
                window.open(url, '_blank');
                break;
            case 2:
                var url = "html/brand.html";
                window.open(url, '_blank');
                break;
            case 3:
                var url = "html/media.html";
                window.open(url, '_blank');
                break;
            case 4:
                var url = "html/forum.html";
                window.open(url, '_blank');
                break;
        }

    });
});
